Comminuting apparatus

ABSTRACT

A comminuting apparatus is provided having a frame, a set of overlapping scissor rolls, a shear outtake manifold, and a pneumatic conveyor. The frame has an enclosure with an entrance for receiving waste material. The set of overlapping scissor rolls includes a feed scissor roll and a recirculation scissor roll, both the feed scissor roll and the recirculation scissor roll being carried for co-rotation within the enclosure and operative to comminute the waste material into subdivided pieces by drawing the received waste material beneath the feed scissor roll and up between the feed scissor roll and the recirculation scissor roll. The shear outtake manifold is beneath the scissor rolls and is configured to collect the subdivided pieces of waste material. The screen is interposed between the set of scissor rolls and the shear outtake manifold and is operative to permit undersized smaller pieces of a size less than a predetermined size to pass therethrough and to prevent oversized pieces of a size greater than a predetermined size from passing therethrough. The pneumatic conveyor comprises a source of air flow. A pneumatic duct communicates with an upstream end of the shear outtake manifold and is operative to deliver an airstream from the source of air flow into the shear outtake manifold. The airstream entrains the subdivided pieces and removes the subdivided pieces from the shear outtake manifold.

RELATED PATENT DATA

This patent resulted from a continuation application of U.S. patentapplication Ser. No. 09/419,822, filed Oct. 15, 1999, entitled“Downstream Pneumatic Recirculation Comminuting Apparatus”, naming JereF. Irwin as inventor, and which will issue as U.S. Pat. No. 6,644,570 onNov. 11, 2003, the disclosure of which is incorporated by reference.

TECHNICAL FIELD

This invention relates to apparatus for comminuting solid wastematerials such as plastic sheet material.

BACKGROUND OF THE INVENTION

The manufacture and forming of many products from plastic producessignificant amounts of plastic waste material. Applicant has previouslyinvented several unique apparatus for comminuting severable wastematerial, particularly plastic sheet material, into small, ratheruniform particles or pieces that can be readily recycled or disposed ofin an environmentally acceptable manner. Several generations of productline have been sold by Irwin Research & Development, Inc., under theproduct name “Chesaw” and have gained commercial success. One such priorinvention is the subject of the Irwin, et al, U.S. Pat. No. 4,687,144granted Aug. 18, 1987. Other such prior inventions are the subject ofU.S. Pat. Nos. 5,836,527; 5,860,607; and 5,893,523. However, additionalimprovements are needed, especially due to the use of thicker, orheavier, plastic sheet material when forming deep draw parts and furtherdue to increases in operating speed that have been realized with motorshaving increased horsepower and/or torque. As a consequence, there hasbeen found to be an increased tendency for subdivided particles toaccumulate within a shear outtake manifold so as to collect and clogsuch manifold, which can significantly reduce operating speeds andthroughput.

The first prior invention of U.S. Pat. No. 4,687,144 was a vastimprovement over various types of hammermills that had previously beenused. The hammermills were quite bulky, extremely noisy, and prone tosubstantial damage when the mill received foreign material that it couldnot comminute. Although such prior Irwin, et al, invention was a vastimprovement and was commercially successful, particularly in view ofhammermills, it was rather expensive to manufacture and sometimes noisyin operation when processing certain materials. Furthermore, it wasunable to satisfactorily comminute rather high density plasticmaterials.

The remaining prior inventions identified above were directed toimprovements over the invention of U.S. Pat. No. 4,687,144. Suchimprovements were directed to improving the amount of comminutedmaterial that could be generated in a given amount of time, to improvethe manner in which the comminuting apparatus operated, and/or toenhance the ability of the comminuting apparatus to efficientlysubdivide pieces of material that are otherwise difficult to comminute.

As an example, U.S. Pat. No. 5,836,527 was an improvement over theinvention of U.S. Pat. No. 4,687,144. More particularly, an improvedcomminuting apparatus is provided which can significantly increase theamount of comminuted material produced in a given amount of time. Suchdevice is relatively less expensive to manufacture, is quieter tooperate, and provides an ability to comminute a wider variety of solidwaste materials. More particularly, the solid waste comminutingapparatus carries material that is severed in the device via anairstream through a fan. Subdivided pieces of material are directed viathe fan to a separator screen which is mounted within a centrifugalhousing. The airstream draws a relative vacuum beneath the separatorscreen that carries small pieces through the separator screen into anouter volute chamber for discharge from the apparatus. Large pieceswhich are not capable of passing through the separator screen arerecycled through a recycle outlet and a recycle conduit back to scissorrolls of the device for further size reduction. However, the complexityof the apparatus and the number of parts needed to construct theapparatus increased over the device of U.S. Pat. No. 4,687,144, whichhas proven undesirable for certain applications.

As another example, U.S. Pat. No. 5,860,607 is directed to an apparatusfor comminuting waste materials, and includes a feed roll for feeding acontinuous sheet of waste material into a shear intake manifold at adesired line speed and directing the waste material to scissor rolls. Anadditional feature includes a screw conveyor for recirculatingsubdivided pieces of comminuted material. More particularly, a feed rolldelivers solid waste material into overlapping scissor rolls at adesired line speed. A pneumatic conveyor, in the form of an Archimedesscrew, delivers the subdivided pieces of comminuted material for sortingand reprocessing. This improvement reduced the tendency for comminutedmaterial to collect or pile up in the shear outtake manifold. However,this improvement also increased the complexity of the comminutingapparatus, requiring the addition of a feed roll and a screw conveyor inaddition to a pair of scissor rolls.

As yet another example, U.S. Pat. No. 5,893,523 is directed to anapparatus for comminuting waste material having feed roll deliveryfeatures. A feed roll is rotatably carried by a frame for directingwaste material to a set of overlapping scissor rolls which shear wastematerial into subdivided pieces as the material passes between thescissor rolls. A separator screen is carried by the frame in associationwith at least one of the scissor rolls for separating subdivided pieceshaving a size less than a predetermined size, and for recirculatingsubdivided pieces having a size greater than a predetermined size.However, a separate feed roll is needed in addition to a pair of scissorrolls which complicates the machine. Furthermore, there is still atendency for certain subdivided pieces to clog the shear outtakemanifold.

The present invention provides a vastly improved comminuting apparatusthat is not only able to process significantly greater amounts ofmaterial in a given time, it is also better able to recirculate and sortsevered solid waste material utilizing an apparatus that is less likelyto clog from subdivided pieces accumulating within the shear outtakemanifold. The improved comminuting apparatus of the present invention isformed with a simplified construction having fewer moving parts, provesmore reliable and less costly to manufacture, is easier to maintain andrepair, and is more efficient to operate. It is also better able tosever a wider variety of different types of materials over a broaderrange of line speeds with increased levels of throughput of a web ofmaterial being received from a processing machine. Accordingly, thepresent invention provides an apparatus that is able to better movesubdivided solid waste material through the comminuting apparatuswithout clogging in a relatively efficient and cost-effective manner,while also being able to handle a wide variety of severable materials athigher operating speeds and material feed rates.

The present invention provides a vastly improved comminuting apparatusthat is also better able to sort severed solid waste material throughthe separator screen and withdraw such waste material from the shearouttake manifold, particularly in an apparatus having a simplifiedconstruction with fewer parts, which is less costly to manufacture,maintain and repair, and is more reliable.

SUMMARY OF THE INVENTION

A self-feeding comminuting apparatus is provided having improvedpneumatic conveyor and material extraction features. According to oneimprovement, a pair of overlapping scissor rolls cooperate to feed wastematerial between the pair of scissor rolls to a recycle manifoldsection. The recycle manifold section delivers subdivided pieces to oneof the scissor rolls to recycle the subdivided pieces for sorting and/orrecirculation between the pair of scissor rolls for further subdividing.According to another feature, a pneumatic conveyor communicates with theshear outtake manifold to generate an airstream through the shearouttake manifold of sufficient velocity to entrain and remove thesubdivided pieces from the shear outtake manifold where they wouldotherwise tend to collect and clog the manifold.

According to one aspect of the invention, a comminuting apparatus isprovided which includes a frame, a set of overlapping scissor rolls, ashear outtake manifold, a screen and a pneumatic conveyor. The frame hasan enclosure with an entrance for receiving waste material. The set ofoverlapping scissor rolls includes a feed scissor roll and arecirculation scissor roll, both the feed scissor roll and therecirculation scissor roll being carried for co-rotation within theenclosure and operative to comminute the waste material into subdividedpieces by drawing the received waste material beneath the feed scissorroll and up between the feed scissor roll and the recirculation scissorroll. The shear outtake manifold is beneath the scissor rolls and isconfigured to collect the subdivided pieces of waste material. Thescreen is interposed between the set of scissor rolls and the shearouttake manifold and is operative to permit undersized smaller pieces ofa size less than a predetermined size to pass therethrough and toprevent oversized pieces of a size greater than a predetermined sizefrom passing therethrough. The pneumatic conveyor comprises a source ofair flow. A pneumatic duct communicates with an upstream end of theshear outtake manifold and is operative to deliver an airstream from thesource of air flow into the shear outtake manifold. The airstreamentrains the subdivided pieces and removes the subdivided pieces fromthe shear outtake manifold.

One advantage of the invention is provided in a simplified constructionhaving a pneumatic conveyor with a pneumatic recirculation duct, ortube, that generates an airstream through the shear outtake manifold ofsufficient velocity to entrain subdivided particles and remove suchparticles from the shear outtake manifold in order to more effectivelyremove the material from the comminuting apparatus and prevent cloggingtherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a plan view of a preferred embodiment of the apparatusillustrating the top exterior of the apparatus with one waste materialentrance having a portion broken away to show the scissor rolls andscreen.

FIG. 2 is a front view of the apparatus illustrated in FIG. 1.

FIG. 3 is a left side view of the apparatus illustrated in FIGS. 1 and2.

FIG. 4 is a right side view of the apparatus illustrated in FIGS. 1 and2.

FIG. 5 is an enlarged transverse vertical cross-sectional and partialview taken along line 5—5 in FIG. 1 illustrating the interior of theapparatus.

FIG. 6 is a series of illustration views of the waste material and thereduction of the waste material into smaller and smaller particles ofthe material as it is progressively processed and reduced to a desiredparticulate size.

FIG. 7 is a product flow illustrated diagram corresponding to the viewof FIG. 1 and showing the flow path of the waste material through theapparatus as the material is being progressively processed and reducedto the desired particulate size.

FIG. 8 is an isolated vertical cross-sectional view taken along line 8—8in FIG. 10 of a set of scissor roll rings illustrating the initialentrance and feeding of a piece of waste material between the scissorrolls.

FIG. 9 is an isolated vertical cross-sectional view similar to FIG. 8taken along line 9—9 in FIG. 10, except showing the scissor roll ringsincrementally rotated to feed and sever the piece of waste material.

FIG. 10 is a cross-sectional view taken along line 10—10 in FIG. 4 butwith the screen removed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

A preferred embodiment of the invention is illustrated in theaccompanying drawings particularly showing a waste comminuting apparatusgenerally designated with the numeral 10 in FIGS. 1–5 for receivingsolid waste material 12, for reducing the solid waste materialprogressively into smaller and smaller sizes until the desired smallparticulate or piece size is obtained, and for withdrawing the materialfrom the apparatus as illustrated in FIG. 6.

Applicant's invention utilizes a pneumatic duct, or pipe, which deliversair flow from a source of air flow into a shear outtake manifold withinapparatus 10 in order to entrain and withdraw subdivided particles fromwithin the manifold and outside of the apparatus for collection. Recentattempts to comminute heavier and thicker materials, such as areutilized in deep draw plastic forming operations, have required the useof drive motors having greater horsepower and/or torque. As aconsequence, a larger mass of subdivided material collects within theshear outtake manifold of such comminuting apparatus since highervolumes of subdivided material are generated therein. For the case whereapparatus 10 is able to generate subdivided material at an increasedrate, such material tends to collect within the shear outtake manifoldwhere it piles up, similar to sand piling up in the form of a sand dune.In order to enable the comminuting of a greater variety of products, andto comminute at higher operating rates and with materials having greaterdensity, improvements have been identified and addressed via Applicant'sinvention as described below. Additionally, such improvements have beenrealized without significantly adding additional moving parts to theconstruction of apparatus 10.

It should be noted that apparatus 10 is very compact even though thematerial is progressively reduced in size in several stages to a desiredpredetermined small size. The predetermined small piece size willgenerally depend upon the desires of the customer, the end use, and theparticular material being comminuted. The solid waste material 12,illustrated in FIG. 6, is progressively reduced to subdivided pieces 14a through 14 e. When the subdivided pieces are generally reduced to thedesired small size, 14 e, they are removed from the apparatus as thefinal product. Those subdivided pieces that have not been sufficientlyreduced to the desired small size are reprocessed or recycled until theyare sufficiently reduced to the desired size.

The apparatus 10 has a general frame 16 that may be self-supported oraffixed to other apparatus, such as the discharge of a thermal-forming,or thermoforming, machine, for receiving the solid waste material 12directly from a thermoforming machine, reducing the material for re-use,and withdrawing the material from the apparatus for collection andstorage. Frame 16 generally includes a general enclosure 18 thatincludes a front wall 20, side walls 22 and 24, a back wall 26, a bottomwall 28, and a top wall 30. Top wall 30 has a material receiving duct 32having a material entrance 41 (see FIGS. 1–4), through which the solidwaste material is fed into apparatus 10. Frame 16 may be supported onlegs 36 that each have individual pairs of wheels 38 at each end. Frame16 preferably includes walls 20, 22, 24, 26, 28 and 30, upper framemembers 40, 42, 44 and 48 and cross-members 46 and 47 that are variouslyillustrated in FIGS. 1–5.

Within enclosure 18, two scissor rolls 50 and 52 are mounted in anintermeshing relationship for rotation in opposite directions, orco-rotation, in coordination with each other to receive the solid wastematerial 12 after being delivered therebetween via scissor roll 50.Scissor roll 50 provides a feed roll, delivering sheet material 12between scissor rolls 50 and 52 to shear the solid material as thematerial passes between scissor rolls 50 and 52 (see FIG. 5). Scissorrolls 50 and 52 are each supported at each end by a bearing similar tobearing 157 of FIG. 10.

Apparatus 10 includes a scissor roll drive generally designated withreference numeral 70 illustrated in FIGS. 1, 2 and 4. Scissor roll drive70 comprises a drive motor assembly having a motor 78 connected to aspeed reduction gearbox 80. Gearbox 80 is operatively connected to ashaft 64 for rotating, or driving, shafts 64 and 66 counter to eachother in the directions illustrated in FIGS. 3, 5, 7, 8 and 9. Shafts 64and 66 are geared together for co-rotation as shown in FIG. 3.

More particularly, scissor roll 50 includes shaft 64 upon which gear 74is rigidly affixed at one end. Similarly, scissor roll 52 includes shaft66 upon which gear 75 is rigidly affixed at a corresponding end. Scissorroll 52 is driven for opposite rotation than scissor roll 50 by way ofintermeshing gears 75 and 74, respectively (see FIG. 3). Gears 74 and 75are provided at an end opposite from drive 70. In this manner, drive 70drives shaft 64 for rotation, with shaft 66 being driven in co-rotation(opposite rotation, but journalled together), which causes scissor rolls50 and 52 to comminute material presented therebetween.

Furthermore, scissor rolls 50 and 52 are positioned within enclosure 18between an intake manifold 122 that receives the material throughentrance 62 and a recycle manifold 124. The material, after passingthrough the scissor rolls 50 and 52 from beneath, ascends into recyclemanifold 124 (see FIG. 5) which communicates with a recirculation cavity125 via recycle flow path 126.

Scissor roll 50 is mounted on shaft 64 which rotates about axis 81 (seeFIG. 5). Scissor roll 52 is mounted on shaft 66 which rotates about axis83. According to one construction, axes 81 and 83 are substantiallyparallel with each other, both extending horizontally, and extendingbetween the side walls 22 and 24. However, scissor roll 50 is elevatedrelative to scissor roll 52 such that axis 81 and axis 83 lie in acommon plane that is inclined relative to a horizontal plane. Accordingto one construction, the resulting inclined plane lies at an angle fromabout 15 to about 45 degrees. Axes 81 and 83 are positioned so thatscissor rolls 50 and 52 have sufficient overlap to shear the materialbetween the scissor rolls as the material passes between the rolls.However, the particular construction and arrangement of scissor rolls 50and 52 within apparatus 10 is not critical to the implementation ofApplicant's invention. Similarly, the provision of a separating screen60 therebeneath is not necessary in order to implement the benefits ofApplicant's invention.

As shown in FIGS. 1, 2 and 4, drive motor 78 of scissor roll drive 70comprises a three-phase AC motor, such as a 50-hp AC motor. To date,prior art constructions have used a substantially smaller-sized motor.However, it has been discovered that certain comminuting applicationsrequire a greater amount of torque and horsepower in order tosuccessfully comminute certain materials. Increasing the horsepower andtorque generally increases the amount of material that is depositedwithin shear outtake manifold 120 which tends to collect and clog withinsuch manifold. Accordingly, the novel features of Applicant's inventionare provided on apparatus 10 in order to ensure the removal ofsubdivided pieces from within shear outtake manifold 120 so as toprevent accumulation and clogging of small size pieces 14 e therein.

According to an optional construction, motor 70 comprises a variablespeed AC drive motor, or servo motor, and a flux vector AC drive (notshown), which is typically housed within an electrical cabinet (notshown) that is associated with the apparatus. More particularly, whereinmotor 78 is a servo drive motor, a sensor can be provided for detectingcondition of the material that is entering apparatus 10 such that a feedvelocity can be regulated by controlling the rotational speed of scissorrolls 50 and 52. Details of one such alternative construction aredescribed in Applicant's pending U.S. patent application Ser. No.09/335,142, entitled “Self-Feeding Comminuting Apparatus Having ImprovedDrive Motor and Recirculation Features”, naming Jere F. Irwin asinventor, and filed on Jun. 16, 1999. Such U.S. patent application Ser.No. 09/335,142 is herein incorporated by reference.

As shown in FIGS. 1 and 2, motor 78 is carried by bracket, or plate, 98via gearbox 80, which is likewise mounted to frame 16 (of apparatus 10).Gearbox 80 is further secured to frame 16 by additional framework (notshown) such as by use of struts that are tied to side wall 24 and frame16. Furthermore, a belt 94 couples motor 78 to drive gearbox 80 andshaft 64. Belt 94 is carried about a pair of pulleys (not shown), oneattached to motor 78 and another attached to gearbox 80. Alternatively,a chain can be substituted for belt 98 wherein sprockets are substitutedfor the pulleys. A cover 92 affixes to bracket 98 to encase belt 94 andthe associated pulleys.

As shown in FIG. 5, shafts 64 and 66 are supported for rotation at eachend by respective bearings 157 (see FIG. 10). Each of shafts 64 and 66has hexagonal cross-sectional profiles, providing angular drive surfaces158 (see FIGS. 8 and 9).

Each of scissor rolls 50 and 52 includes a plurality of scissor rings160 in which each of the rings 160 has an outer circular peripheralsurface 162 and an inner hexagonal bearing surface 164 that iscomplementary to the profile of shafts 64 and 66 so that the scissorrings 160 rotate in response to the rotation of shafts 64 and 66 (seeFIGS. 8 and 9). Each of the scissor rings 160 includes side surfacesthat form shearing edges 168 with the outer peripheral surface 162 (seeFIG. 10).

In the preferred embodiment, each of scissor rings 160 has evenlyangularly spaced finger knives 170 formed integrally on the scissorrings 160 and projecting radially outward of the surface 162 and forwardin the direction of rotation for gripping, puncturing and transverselycutting the solid material 12, as illustrated in FIGS. 8 and 9. Each ofthe finger knives 170 includes a projecting body 171 that projectsradially outward from the peripheral surface 162 and projects forward inthe direction of rotation. Each of the finger knives 170 includes a sideshearing surface 172 and an undercut surface 174, forming a sharp knifepoint 176. The scissor ring finger knives 170 are intended to grip,puncture and transverse the cuttage piece as it is being sheared betweenrings 160.

Each of the scissor rolls 50 and 52 further includes a plurality of ringspacers 180. Each spacer 180 has a circular outer peripheral surface 182and an inner hexagonal surface 184 (see FIGS. 8 and 9). Circular outerperipheral surface 182 of each spacer 180 has a groove sized to receivethe corresponding stripper finger 58 and 59 of one of frame members 42and 40, respectively (see FIG. 5). The corresponding circumferentialgroove is not indicated with a reference numeral due to its relativelythin profile in order to facilitate simplification of the drawings. Thecorresponding groove is sized such that fingers 58 and 59 are smoothlyand cleanly received therein, preventing fingers 58 and 59 from scrapingthe sides of each adjacent scissor ring 160.

Accordingly, each of the ring spacers 180 has a width that is slightlygreater than the width of the spacer rings 160. Each of the spacer rings160 and ring spacers 180 are alternately positioned on shafts 64 and 66so that a scissor ring 170 on one scissor roll opposes a correspondingring spacer 180 on the other scissor roll, creating a circularinter-roll cavity 186 (see FIG. 10) between the adjacent rings andoutward of the intermediate ring spacers 180. Once the material 12 iscut and sheared, it is received in the inter-roll cavity 186 (see FIG.10) and passes between scissor rolls 50 and 52 into the recyclingmanifold 124.

The axes 81 and 83 of the scissor rolls are sufficiently spaced so thatthere is a slight overlap of approximately one-eighth inch (⅛″) in theprofile of the scissor rings so that as they are rotated, the materialis sheared by the shearing edges 168 and the finger knife 170 as aprofile of the scissor ring 160 moves into the circular inter-rollcavity 186 of the opposing ring spacer 180 (see FIG. 10).

As shown in FIG. 5, once material 12 is cut and sheared by scissor rolls50 and 52, it is carried into recycle manifold 124, which communicateswith, and is formed in part by recycle flow path 126 and recirculationcavity 125. Once cut and sheared material 12 collects in manifold 124 toa sufficient height, it cascades over the top portion of frame member40, falling into recirculation cavity 125, where it is recycled viascissor roll 52. More particularly, scissor roll 52 draws the material12 between roll 52 and screen 60, and upward between scissor rolls 50and 52 for further comminuting. In this manner, cut and sheared materialis again fed via scissor roll 52, which serves as a feed roll, back intoscissor rolls 50 and 52 by passing it between scissor roll 52 and screen60 where individual teeth on scissor ring 160 convey and deliver sheetof material 12, along with recirculated cut and sheared material back toroll 52 for further delivery, sorting and/or severing.

Material 12, which has passed over flow path 126 and has been directedto scissor roll 52, is thus recirculated via projecting bodies 171 (seeFIG. 8) of scissor ring 160 back to scissor roll 52, where it isreprocessed between rolls 50 and 52 for delivery back into recyclingmanifold 124.

Particles 14 e of sufficiently small size are separated out via aperforated plate, or separator screen, 60, which is provided immediatelybelow and adjacent to rolls 50 and 52, conforming substantially to theirgeneral nested bottom edge configuration. Here, screen 60 has the shapeof a bi-concave perforated plate. Apertures in screen 60 are sized suchthat sufficiently small particles 14 e drop through screen 60 where theyare collected via a collector tray, or drop pan, 84. Tray 84 isreleasably supported to frame 16 via a pair of handle release assemblies(not shown). Details of such releasable support and handle assembly areomitted here but are disclosed in Applicant's U.S. patent applicationSer. No. 09/335,142, previously incorporated herein by reference. Whenheld in place, tray 84 also holds screen 60 in place, which facilitatesquick and efficient disassembly for cleaning and maintenance.Optionally, such parts can be welded together.

Collected particles 14 e, present within tray 84, are then withdrawnthrough an outlet 118 (see FIGS. 5 and 7) by way of a pneumatic conveyor72, which draws a vacuum, and a pneumatic duct 62, which generates anairstream. An inlet 119 is provided at an opposite end of tray 84 fromoutlet 118 in order to deliver an airstream from inlet 119 to outlet118, which helps remove particles 14 e from shear outtake manifold 120.Particles 14 a–d which are not sufficiently small enough to pass throughscreen 60 continue to be recirculated between rolls 50 and 52 viascissor roll 52.

Additionally, it has been discovered that some of the recirculatedpieces 14 a–e in recycle manifold 124 are sifted, or passed, in areverse direction along flow path 127 where they fall backwards, or inreverse, between inner-roll cavities 186 (see FIG. 10) and return toscreen 60. In this manner, particles which have sufficiently small size14 e are sifted by falling back via flow path 127 to screen 60 wherethey are collected in tray 84. Likewise, particles that fall back, butthat are not sufficiently small in size, such as particles 14 a–d, arepassed down through rolls 50 and 52 where they are reprocessed anddelivered upwardly to be further recycled via manifold 124, flow path126 and recirculation cavity 125.

As shown in FIG. 5, a plurality of feeding fingers 54 are providedadjacent scissor roll 50 in order to further facilitate the piercing anddriving of material as it is fed from intake manifold 122 betweenscissor roll 50 and screen 60. More particularly, each individualfeeding finger 54 comprises a metal bar sized to fit in the gap providedbetween adjacent scissor rings 160 (see FIG. 10). Similarly, a pluralityof metering fingers 56 are provided along scissor roll 52 to meter thedelivery of recycled, or recirculated, material from recirculationcavity 125 and between scissor roll 52 and screen 60. Each meteringfinger 56 is configured to be received within the inner space cavityformed between adjacent scissor rings 160 (see FIG. 10).

As shown in FIG. 5, screen 60 is carried at each end by respective edgeportions of tray 84 so as to be presented in inter-nested adjacentrelation with scissor rolls 50 and 52. Screen 60 is quickly and easilyremoved for maintenance, repair and/or cleaning by releasing handrelease assemblies (not shown) such that retaining loops can bereleasably removed from the clasp bars which facilitate the dropping oftray 84 and removal of screen 60. Screen 60 and tray 84 are re-securedby latching the loops onto the clasp bars and securing the respectivehand release assemblies, including pivotally latching and securing theindividual handles. When released to a drop position, tray 84 can bepivotally dropped for cleaning and maintenance. Additionally, screen 60is further secured into engagement with cross-members 46 and 47.

Intake manifold 122 is configured to receive sheet material fromentrance 41 of material receiving duct 32, illustrated in FIGS. 1 and 2.New solid waste material 12 enters through one of material entrance 41via associated material receiving duct 32 and subdivided materialrequiring additional recycling is recirculated via a recycling manifoldsection 124 where it is re-delivered by way of recycle flow path 126 torecirculation cavity 125, or it is alternatively returned via reversesort path 127 for sifting in screen 60 or further severing andsubdividing via rolls 50 and 52.

Material receiving duct 32 includes a front plate 37 and a back plate 39which are pivotally supported atop apparatus 10 via adjustable brackets51, 53 and 55, 57, respectively. Brackets 51, 53 and 55, 57 areadjustably positioned via fasteners (not shown) so as to adjust therelative height of plates 37 and 39 for a desired application. Forexample, apparatus 10 is commonly provided beneath a horizontallyconfigured trim press, and brackets 51, 53 and 55, 57 are verticallyadjusted such that plates 37 and 39, respectively, are provided at anelevational height that ensures guided delivery of material intoentrance 41. Furthermore, plates 37 and 39 are pivotally supported atopbrackets 51, 53 and 55, 57, respectively, so that plates 37 and 39 canbe desirably oriented by manipulating the positions of plates 37 and 39simply by hand. Accordingly, such hinges are constructed with aclearance fit so as to impart resistance that enables positioning ofplates 37 and 39 into a desired orientation where they remain until theyare reconfigured into a new position by hand via an individual who isconfiguring apparatus 10 for use in a desired operating environment.

The shear outtake manifold 120 includes an inlet 119, an outlet 118, anda collection tray, or pan, 84 with a pneumatic conveyor 72 that includesa pneumatic duct 62 (FIGS. 5 and 7), and a source of air flow thatcooperate to facilitate the removal of the smaller-sized severed pieces14 e from the outtake manifold 120 and to entrain such pieces 14 e in anairstream via pneumatic duct 62, shear outtake manifold 120, outtakepipe 114 (see FIG. 7), and the source of air flow. According to oneconstruction, the source of air flow is provided by pneumatic conveyor72. According to one construction, pneumatic conveyor 72 is acentrifugal fan 110 (see FIG. 1). Inlet 119 communicates with anairstream conduit comprising pneumatic duct, or pipe, 62 for directingan airstream through shear outtake manifold 120 that entrains subdividedpieces and delivers them via outtake pipe 114 to outer volute duct 135along flow path 136 to a product outlet 112 (see FIG. 8). Centrifugalfan 110 also draws a vacuum via outtake pipe 114 at outlet 118 tofurther assist withdrawal of particles 14 e from manifold 120.

Pneumatic duct 62 is affixed at a first end to centrifugal fan 110, andat a second end to inlet 119 (as shown in FIG. 1). Furthermore,pneumatic duct 62 is affixed to frame 16 via clamps 67 and 68,respectively, as shown in FIG. 2.

Apparatus 10 includes pneumatic conveyor 72, as shown in FIG. 7, forconveying subdivided pieces 14 from outtake manifold 120 and directingthe pieces to a product outlet 112. Product outlet 112 ejects the pieces14 e where the sufficiently small subdivided pieces 14 e are collectedin a storage vessel (not shown) for later recycling.

The pneumatic conveyor 72 includes centrifugal fan 110 which provides asource of air flow to pneumatic duct, or pipe, 62 for delivering anairstream of sufficient velocity and volume within shear outtakemanifold 120 to remove the subdivided pieces from shear outtake manifold120 and to entrain the pieces 14 e in the airstream (see FIGS. 5 and 7).

The centrifugal fan 110, illustrated in FIG. 7, includes a housing 130having a central propeller section 115, a peripheral volute section 133,and a first outer volute duct 135. The central propeller section 115includes a central inlet 134 with a propeller assembly 132 mountedwithin the central propeller section 115. The propeller assembly 132includes a shaft 131 with radial blades 137 extending radially outwardfor directing the air from the central inlet 134 radially outward andtangential into the peripheral volute section 133. A motor 116 (seeFIG. 1) is connected to the shaft 131 (see FIG. 7) for rotating theblades 137 at the desired speed to obtain an airstream having thedesired velocity and volume.

Centrifugal fan 110 communicates with first outer volute duct 135 andproduct outlet 112 for discharging the small particles 14 e that havepassed through the separator screen 60 via outtake pipe 114.

Pneumatic duct 62 delivers air from centrifugal fan 110 to an upstreamend of shear outtake manifold 120, via inlet 119. More particularly, asecond outer volute duct 140 is provided at a location along peripheralvolute section 133 that is downstream of first outlet volute duct 135.Accordingly, small particles 14 are discharged via first outer voluteduct 135 such that little or no particles 14 e are delivered to secondouter volute duct 140 while a sufficient source of air flow is deliveredvia pneumatic duct 62. Centrifugal fan 110, second outer volute duct140, and pneumatic duct 62 cooperate to provide a pneumatic conveyor 72that delivers a relatively high pressure airstream to the upstream endof shear outtake manifold 120 via inlet 119. Such relatively high streamflow path extends from an upstream end of shear manifold outtake 120,from inlet 119 to outlet 118. Accordingly, subdivided pieces that mightotherwise collect within shear outtake manifold 120 are agitated,entrained and carried by such air flow through manifold 120 so as toremove such particles, and to prevent accumulation or clogging of suchparticles therein.

As illustrated in FIGS. 5 and 7, the cross-frame members 40 and 42, eachcomprising a stripper plate, each have notched stripping fingers 58 and59, respectively, formed along an edge thereof projecting between thescissor rings 160 and into the inter-roll cavities 186 along the lowerprofile of the scissor rolls 50 and 52 to strip any of the subdividedpieces from between the scissor rings 160 after the pieces have beensevered. In one version, each finger is secured to each plate with oneor more fasteners (not shown). Each finger 58, 59 rides in acomplementary groove (not numbered) in the radial outer surface of ringspacer 80 (of FIG. 5).

During the operation of the apparatus 10, solid waste material 12 is fedinto the apparatus 10 through entrances 62 of duct 32 (see FIGS. 1, 3and 4) and into the intake manifold 122 where it is directed to thescissor roll 50 (see FIGS. 5 and 7). Scissor roll 50 then moves thematerial along feeding fingers 54, pulling the material 12 betweenscissor roll 50 and feeding fingers 54. The engaged material isdelivered by scissor roll 50 along screen 60. In some cases, feedingfingers 54 can also help to sever material 12 during delivery betweenscissor rolls 50 and 52. Scissor roll 50 then further engages thematerial, causing some of the material to rip and sever, as roll 50 isrotated. Scissor roll 50 then delivers or circulates the material alongscreen 60 for sorting and between rolls 50 and 52 where it is engagedand severed.

As the delivered material 12 engages rolls 50 and 52, material 12 isgripped by the finger knives 170 (see FIGS. 8 and 9) and pulled betweenthe scissor rolls 50 and 52, with the scissor rings 160 and its shearingedges 168 shearing the solid waste material into subdivided pieces. Aspreviously mentioned, the finger knives 170 grip the material, puncturethe material and transversely cut the material even further as it passesbetween the rolls. The severed pieces 14 a–14 e (see FIG. 6) then ascendinto the recycle manifold section 124. The stripper fingers 58 and 59strip any severed pieces from the rolls 52 and 50, respectively, andremove them into the recycle manifold section 124.

After material and subdivided pieces 14 a–e are delivered to scissorroll 50, scissor roll 50 in combination with scissor roll 52 furtherdelivers the pieces along screen 60 where small subdivided pieces 14 eare separated from the remaining material and pieces. Those subdividedpieces that are larger than the apertures or holes in the separatorscreen 60 are carried along rolls 50 and 52 where they are deliveredbetween rolls 50 and 52 for further severing and subdividing, orcomminuting. The further subdivided pieces are then delivered intorecycle manifold section 124. Such further subdivided pieces 14 a–14 eare then either re-delivered via recycle flow path 126 to recirculationcavity 125 for further delivery and subdividing, or are received in areverse direction via reverse-direction sort path 127 back along screen60 where sufficiently small particles 14 e are separated out throughscreen 60 and remaining portions are further subdivided between rolls 50and 52. The small pieces 14 e that pass through the separator screen 60are directed from the apparatus via pneumatic conveyor 72, including fan110 and pneumatic duct 62, through the product outlet 118 to a pneumaticconveyor 72 for delivery to final product outlet 112.

The large particles or pieces 14 a–14 e will be continually recycledthrough recycle flow paths 126 or 127 until their size is reduced belowthat of the preselected size of the apertures of the separator screen60. Screen 60 can be easily replaced in order to provide apertures witha desired size for implementing a desired sort of particles. Screen 60can be constructed from screen material or any suitable perforated sheetor plate, or other suitable construction.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A comminuting apparatus, comprising: a frame having an enclosure withan entrance for receiving waste material; a set of overlapping scissorrolls including a feed scissor roll with a plurality of finger knivesand a recirculation scissor roll with a plurality of finger knives, boththe feed scissor roll and the recirculation scissor roll carried forco-rotation within the enclosure to provide an entrance nip beneath andbetween the feed scissor roll and the recirculation scissor roll andoperative to comminute the waste material into subdivided pieces bydrawing the received waste material beneath the feed scissor roll and upbetween the feed scissor roll and the recirculation scissor roll; aplurality of feeding fingers carried by the frame, one finger knifeconfigured to intermesh in overlapping relation with an adjacent pair ofthe finger knives of the feed scissor roll during rotation of the feedscissor roll; a plurality of metering fingers carried by the frame, onemetering finger configured to intermesh with an adjacent pair of thefinger knives of the recirculation scissor roll during rotation of therecirculation scissor roll; a shear outtake manifold beneath the scissorrolls and configured to collect the subdivided pieces of waste material;a screen interposed between the set of scissor rolls and the shearouttake manifold and operative to permit undersized smaller pieces of asize less than a predetermined size to pass therethrough and to preventoversized pieces of a size greater than a predetermined size frompassing therethrough; and a pneumatic conveyor comprising a source ofair flow and a pneumatic duct communicating with an upstream end of theshear outtake manifold and operative to deliver an airstream from thesource of air flow into the shear outtake manifold that entrains thesubdivided pieces and removes the subdivided pieces from the shearouttake manifold.
 2. The comminuting apparatus of claim 1 furthercomprising a stripper plate having stripping fingers, the stripper platecarried by the frame and the stripping fingers configured to intermeshwith the finger knives of the feed scissor roll to direct subdividedpieces of waste material toward the recirculation scissor roll andrestrict delivery of subdivided pieces of waste material to the feedscissor roll.
 3. The comminuting apparatus of claim 1 further comprisinga recycle manifold provided downstream and above the feed scissor rolland the recirculation scissor roll, the recycle manifold beingconfigured to receive subdivided pieces that have passed between thefeed scissor roll and the recirculation scissor roll.
 4. The comminutingapparatus of claim 1 wherein the feed scissor roll and the recirculationscissor roll are carried by the frame in substantially parallelrelation, wherein the screen is provided substantially beneath the setof scissor rolls, and the shear outtake manifold is providedsubstantially beneath the screen.
 5. The comminuting apparatus of claim1 further comprising a frame member provided along the feed scissor rolland configured to support the plurality of feeding fingers.
 6. Thecomminuting apparatus of claim 5 wherein each of the feeding fingers hasat least one scissor edge configured to interact with a respectivescissor edge on a respective finger knife of the feed scissor roll tohelp sever received waste material that is being delivered beneath thefeed scissor roll for comminuting between the feed scissor roll and therecirculation scissor roll.
 7. The comminuting apparatus of claim 1further comprising a frame member provided along the recirculationscissor roll and configured to support the plurality of meteringfingers.
 8. The comminuting apparatus of claim 7 wherein the meteringfingers are intermeshed with the finger knives of the recirculationscissor roll so as to meter delivery of subdivided pieces of wastematerial for recirculation beneath the recirculation scissor roll forfurther subdividing between the recirculation scissor roll and the feedscissor roll.
 9. The comminuting apparatus of claim 8 wherein each ofthe metering fingers is configured to be received within an inner spacecavity formed between adjacent ones of the finger knives of therecirculation scissor roll.
 10. The comminuting apparatus of claim 9wherein each scissor roll comprises a plurality of adjacent scissorrings, each scissor ring having at least one finger knife, and whereinthe inner space cavity is formed between a respective one of the scissorrings of the feed scissor roll and an adjacent, respective one of thescissor rings of the recirculation scissor roll.
 11. A comminutingapparatus, comprising: a housing having an entrance for receiving wastematerial; a feed scissor roll carried for rotation by the housing andhaving a plurality of scissor rings, each scissor ring provided with aplurality of finger knives; a recirculation scissor roll carried forrotation by the housing and having a plurality of scissor rings, eachscissor ring provided with a plurality of finger knives, the fingerknives of the recirculation scissor roll configured to overlap with thescissor rings of the feed scissor roll with the feed scissor roll andrecirculation scissor roll carried for co-rotation by the housing andconfigured to provide an entrance nip beneath and between the feedscissor roll and the recirculation scissor roll; an array of feedingfingers carried by the housing and configured to intermesh inoverlapping relation with adjacent pairs of the finger knives of thefeed scissor roll during rotation of the feed scissor roll; an array ofmetering fingers carried by the housing and configured to intermesh withadjacent pairs of the finger knives of the recirculation scissor rollduring rotation of the recirculation scissor roll; and a screen providedat least in part along the recirculation scissor roll to withdrawundersized smaller pieces of waste material less than a predeterminedsize to pass therethrough and to recirculate oversized pieces of a sizegreater than the predetermined size for further subdividing between thefeed scissor roll and the recirculation scissor roll.
 12. Thecomminuting apparatus of claim 11 further comprising a shear outtakemanifold provided beneath the scissor rolls and configured to collectthe subdivided pieces of waste material that have passed through thescreen.
 13. The comminuting apparatus of claim 12 further comprising apneumatic conveyor including a source of air flow and a pneumatic ductcommunicating with an upstream end of the shear outtake manifold andoperative to deliver an airstream from the source of air flow into theshear outtake manifold that entrains the subdivided pieces and removesthe subdivided pieces from the shear outtake manifold.
 14. Thecomminuting apparatus of claim 11 wherein the feed scissor roll and therecirculation scissor roll provide a set of overlapping scissor rollsthat intermesh in co-rotation to subdivide waste material therebetween.15. The comminuting apparatus of claim 11 wherein the housing furthercomprises a frame and an enclosure in which the entrance is furtherprovided.
 16. The comminuting apparatus of claim 11 wherein the feedingfingers and the metering fingers are affixed in a stationary positionrelative to the housing and the finger knives of the feed scissor rolland the finger knives of the recirculation scissor roll are carried forrotation relative to the feeding fingers and the metering fingers,respectively.
 17. A comminuting apparatus for subdividing andrecirculating waste material, comprising: a housing with an entrance forreceiving waste material; a set of overlapping scissor rolls each havinga plurality of scissor rings with each scissor ring having a pluralityof finger knives, the scissor rolls comprising a feed scissor roll and arecirculation scissor roll carried for co-rotation by the housing fordelivery of waste material therebetween; a plurality of feeding fingerscarried in a stationary position relative to the housing and configuredto intermesh in overlapping relation with adjacent pairs of the fingerknives of the feed scissor roll; a plurality of metering fingers carriedin a stationary position relative to the housing and configured tointermesh in overlapping relation with adjacent pairs of the fingerknives of the recirculation scissor roll; a stripping plate carried bythe housing and having a plurality of stripping fingers configured tointermesh with the finger knives of the feed scissor roll to directsubdivided pieces of waste material toward the recirculation scissorroll and restrict delivery of subdivided pieces of waste material frombeing delivered to the feed scissor roll; and a screen provided alongthe recirculation scissor roll to withdraw relatively small pieces ofwaste material therethrough and to recirculate relatively large piecesof waste material for further subdividing via the entrance nip betweenthe feed scissor roll and the recirculation scissor roll.
 18. Thecomminuting apparatus of claim 17 further comprising a recycle manifoldprovided downstream and above the feed scissor roll and therecirculation scissor roll, the recycle manifold configured to receivesubdivided pieces that have passed between the feed scissor roll and therecirculation scissor roll.
 19. The comminuting apparatus of claim 17wherein the feed scissor roll is slightly elevated relative to therecirculation scissor roll.
 20. The comminuting apparatus of claim 17wherein the feed scissor roll is driven in a clockwise rotation and therecirculation scissor roll is driven in a counter-clockwise rotation.